Hobby-Eberly Telescope primary mirror alignment metrology system upgrade

Hanshin Lee; Herman Kriel; Chris Robison; Shane Henk; Jayton Lindley

doi:10.1117/12.3020706

11 September 2024 Hobby-Eberly Telescope primary mirror alignment metrology system upgrade

Hanshin Lee, Herman Kriel, Chris Robison, Shane Henk, Jayton Lindley

Author Affiliations +

Proceedings Volume 13094, Ground-based and Airborne Telescopes X; 1309422 (2024) https://doi.org/10.1117/12.3020706
Event: SPIE Astronomical Telescopes + Instrumentation, 2024, Yokohama, Japan

Abstract

The primary mirror (M1) of the Hobby Eberly Telescope (HET) consists of 91 mirror segments in a regular hexagonal shape. The M1’s center of curvature can be accessed from the top of a 90ft-tall tower, located just outside the HET dome. The current alignment metrology system in this tower, called the Center of Curvature Alignment System (CCAS), provides alignment metrology necessary to bring the 91 segments into a single smooth 11-meter diameter spherical surface. This critical function is at risk due to the obsolescence and deficiencies of the aging system. The upgrade includes a suite of advanced metrology instruments to provide improved alignment precision and metrology. In particular, the upgrade features a new dispersed fringe sensing (DFS) device capable of measuring the piston error of all 240 segment edges across the HET’s 11m primary mirror in a single-shot exposure based on wavelength multiplexing, arrayed diffractive components, and spatial filters. This paper summarizes the electro-opto-mechanical design of the system and other design features to be implemented in the upgrade.

Conference Presentation

(2024) Published by SPIE. Downloading of the abstract is permitted for personal use only.

Citation Download Citation

Hanshin Lee, Herman Kriel, Chris Robison, Shane Henk, and Jayton Lindley "Hobby-Eberly Telescope primary mirror alignment metrology system upgrade", Proc. SPIE 13094, Ground-based and Airborne Telescopes X, 1309422 (11 September 2024); https://doi.org/10.1117/12.3020706

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